Garbage collection refers to the process of reclaiming allocated memory (e.g., in Random Access Memory (“RAM”), hard disk space, etc.) that a program is no longer using. Such unused memory is “garbage” to a program because, unless reclaimed, the program cannot use the memory. Therefore, the goal of garbage collection is to identify memory that cannot be accessed in the future, and to reclaim those resources so the system can later use the memory as needed. Otherwise, programs would eventually run out of memory, resulting in poor system utilization and performance.
Garbage collection is a form of automatic memory management, where allocated memory should be reclaimed automatically once it can no longer be accessed by the program. Therefore, the challenge in automatic garbage collection programs often lies in properly identifying memory to reclaim. This challenge is further compounded for garbage collection routines in distributed systems. For solitary systems, garbage collection routines can relatively easily iterate through the system memory to identify and reclaim memory. However, garbage collection is often more complicated for distributed systems. Because distributed systems include a plurality of remotely located components (or systems), distributed systems rely on communication protocols to coordinate among the various components. Messaging between these components often creates bottlenecks, slowing down the garbage collection process. For example, if the distributed system includes a centralized memory that is accessed by a plurality of remote computers, it is often inefficient for the remote computers to communicate with the centralized memory itself to perform garbage collection.
Most garbage collection routines are lengthy and computationally expensive. Additionally, because garbage collection routines typically execute as separate threads (or entirely separate processes) from other applications, it can be difficult to predict when the garbage collection routine will execute relative to other programs. Therefore, the garbage collection process may improperly reclaim memory that will be accessed by other programs in the future.